docs: def integrate(self, fluxunits='photlam'):
          """Integrate the flux in given unit.
  
          Integration is done using :meth:`~Integrator.trapezoidIntegration`
          with ``x=wave`` and ``y=flux``, where flux has been
          convert to given unit first.
  
          .. math::
  
              \\textnormal{result} = \\int F_{\\lambda} d\\lambda
  
          Parameters
          ----------
          fluxunits : str
              Flux unit to integrate in.
  
          Returns
          -------
          result : float
              Integrated sum. Its unit should take account of the
              integration over wavelength. For example, if
              ``fluxunits='photlam'`` is given, then its unit
              is ``photon/s/cm^2``.
  
          """
          # Extract the flux in the desired units
          u = self.fluxunits
          self.convert(fluxunits)
          wave, flux = self.getArrays()
          self.convert(u)
          # then do the integration
          return self.trapezoidIntegration(wave, flux)